Only include the zfs headers where they're currently required to
compile. Unfortunately, including zfs_ioctl.h in user space pulls
in a bunch of internal zfs headers as a side effect. We'll need
to move these structures in to a new shared header to avoid this.
We should not need to add the LIBZPOOL_CPPFLAGS when building the
zed, zinject, zpool, libzfs, ior libzfs_core.
Sponsored-by: https://despairlabs.com/sponsor/
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Rob Norris <robn@despairlabs.com>
Closes#17861
